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Last data update: 2014.03.03

R: Plot Average Effects of Variables in Proportional Odds...

ordAveEffPlot

R Documentation

Plot Average Effects of Variables in Proportional Odds Logistic Regression

Description

For objects of class polr the function plots the average effect of a single variable holding all other variables at their observed values.

Usage

ordAveEffPlot(obj, varname, data, R = 1500, nvals = 25, plot = TRUE, ...)

Arguments

`obj`	An object of class `polr`
`varname`	A string providing the name of the variable for which you want the plot to be drawn.
`data`	Data used to estimate `obj`.
`R`	Number of simulations to generate confidence intervals.
`nvals`	Number of evaluation points of the function
`plot`	Logical indicating whether or not the result should be plotted (if `TRUE`) or returned to the console (if `FALSE`).
`...`	Arguments passed down to the call to `xyplot`

Details

Following the advice of Hanmer and Kalkan (2013) the function calculates the average effect of a variable holding all other variables at observed values and then plots the result.

Value

Either a plot or a data frame with variables

`mean`	The average effect (i.e., predicted probability)
`lower`	The lower 95% confidence bound
`upper`	The upper 95% confidence bound
`y`	The values of the dependent variable being predicted
`x`	The values of the independent variable being manipulated

Author(s)

Dave Armstrong (UW-Milwaukee, Department of Political Science)

References

Hanmer, M.J. and K.O. Kalkan. 2013. ‘Behind the Curve: Clarifying the Best Approach to Calculating Predicted Probabilities and Marginal Effects from Limited Dependent Variable Models’. American Journal of Political Science. 57(1): 263-277.

Examples

library(MASS)
data(france)
polr.mod <- polr(vote ~ age + male + retnat + lrself, data=france)
## Not run: ordAveEffPlot(polr.mod, "lrself", data=france)

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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Type 'demo()' for some demos, 'help()' for on-line help, or
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Type 'q()' to quit R.

> library(DAMisc)
Loading required package: car
Loading required package: effects

Attaching package: 'effects'

The following object is masked from 'package:car':

    Prestige

> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/DAMisc/ordAveEffPlot.Rd_%03d_medium.png", width=480, height=480)
> ### Name: ordAveEffPlot
> ### Title: Plot Average Effects of Variables in Proportional Odds Logistic
> ###   Regression
> ### Aliases: ordAveEffPlot
> 
> ### ** Examples
> 
> library(MASS)
> data(france)
> polr.mod <- polr(vote ~ age + male + retnat + lrself, data=france)
> ## Not run: ordAveEffPlot(polr.mod, "lrself", data=france)	
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>